JP2002174193A - Fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a fuel pump to have excellent pump efficiency. SOLUTION: The groove face shape of a blade groove 12c provided to form a closed blade type blade 12c formed at the outer periphery of an impeller 12, and that of recessed grooves 8e, 9d formed at first and second plates 8, 9 disposed in a closely facing state at the impeller 12 are formed on the basis of a cycloid curve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of a fuel pump mounted on a vehicle or the like.

[0002]

2. Description of the Related Art Generally, in this kind of fuel pump,
A pump unit having an impeller that rotates based on driving of the motor unit, a first plate disposed on one side of the motor unit,
It is known that the impeller is provided with a second plate which is provided between the first plate and the first plate. And in such a thing, by rotating the impeller of the fuel pump accommodated in the fuel tank, the closed blade-like blade groove formed on the outer periphery of the impeller turns the fuel into a swirling flow, and the fuel in the fuel tank is By flowing from the inflow port formed on the second plate side and discharging it into the motor housing constituting the motor unit through the discharge port formed on the first plate side, the fuel passing through the motor housing is discharged. It is configured to be pressure-fed to the fuel injection device side. At this time, the impeller and the first and second plates are arranged in a state of being opposed to each other, while the first and second plates are opposed to the closed blade-like blade grooves formed on the outer periphery of the impeller. Has a concave groove portion, and the fuel is swirled in the fuel flow path formed between the blade groove and the concave groove portion based on the rotation of the impeller, so that kinetic energy based on the rotational force of the impeller is reduced. The fuel is converted into velocity energy of a fluid (fuel), whereby the fuel in the fuel tank is adjusted in flow rate and set to a high pressure state so as to be pumped toward the motor housing.

[0003]

One of the factors for improving the pump efficiency of the fuel pump is the shape of the fuel flow path formed by the blade groove and the concave grooves of the first and second plates. For example, JP-A-63-
As shown in JP-A-63756, the fuel flow path is set based on the relationship between the overall cross-sectional area of the fuel flow path and the thickness of the impeller, and as shown in JP-A-8-144996. It is known that the pump efficiency is increased by setting the shape of the concave groove portion forming the fuel flow path so that the groove width becomes smaller toward the base end side of the blade groove. On the other hand, in recent years, energy conservation has been emphasized in order to protect limited resources, and further improvement in pump efficiency has been demanded, and there has been a problem to be solved by the present invention.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been developed with the object of solving these problems, and has an impeller which rotates based on the driving of a motor unit. A fuel pump comprising: a first plate disposed on one side of a motor unit; and a second plate having the impeller interposed between the first plate and the first plate. The first to form
Each groove surface of the concave groove provided on the inner surface of the second plate is formed based on a cycloid curve. By doing so, the pump efficiency of the fuel pump can be improved, and the fuel consumption can be reduced. In this, a closed blade is formed on the outer periphery of the impeller of the present invention, and a blade groove provided to form the closed blade may be formed based on a cycloid curve. With this configuration,
The efficiency can be further improved. Further, in this case, the radial groove length of the concave grooves of the first and second plates of the present invention can be set to be approximately half of the radial groove length of the blade groove.

[0005]

Next, two embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a fuel pump disposed in a fuel tank.
Has a motor section M formed at one end and a pump P at the other end.
Are formed. The cylindrical motor housing 2 constituting the motor section M has an armature 3 therein. The armature 3 includes an armature shaft 3a, a core 3b integrally fitted on the armature shaft 3a, and a core 3b. 3b
And a plurality of coils 3c wound around the armature shaft 3a
And a commutator 4 having a plurality of commutator pieces 4a to which the coils 3c are electrically connected. On the other hand, a permanent magnet 5 is fixed to the inner peripheral surface of the cylinder of the motor housing 2, and a plurality of brush holders 6 are integrally provided on one end side of the motor housing 2. The brush 6a to be connected is housed.

[0006] The armature 3 supports one end of the armature shaft 3a via a bearing 7a on a cover body 7 arranged so as to cover the opening end on one end side of the motor housing 2, and at the same time, the armature shaft 3a is mounted on the armature shaft 3a. The other end is rotatably supported by the motor housing 2 by being supported via a bearing 8a on a first plate 8 disposed so as to cover the opening end on the other end side of the motor housing 2. 6a is brought into contact with the commutator 4 of the armature 3 in a resilient manner and is supplied with power to the coil 3c.
The armature 3 is configured to rotate integrally with the armature shaft 3a.
Is configured. Further, a fuel supply port 7b is formed integrally with the cover body 7 so as to communicate with the inside of the motor housing 2, and fuel is set to be supplied from the fuel supply port 7b to the fuel injection device side. .

On the other hand, the pump portion P of the fuel pump 1 is opposed to the other end portion of the first plate 8 disposed on the other end side of the motor portion M, in close proximity to the first plate 8, and the outer peripheral portion is the second A second plate 9 fixed to one plate 8,
The pump chamber P is located between the first plate 8 and the second plate 9 facing each other.
R is formed. The first plate 8 is formed with a groove 8b recessed toward one end, and the bearing 8a is disposed in the through hole 8c formed at the center of the groove 8b as described above. The armature shaft 3a is rotatably and pierced. Then, a joint member 10 in which a plurality of connecting pins 10a protrude toward the other end side at the protruding end portion which is the other end portion of the armature shaft 3a protruding toward the pump chamber PR side is housed in the concave portion 8b. It is fixed in a detent shape in the state.

The second plate 9 is formed with a groove 9a facing the first plate groove 8b and recessed toward the other end, and is formed at the center of the groove 9. The other end of the fixed shaft 11 is integrally fixed to the opened through hole 9b so as to be concentric with the armature shaft 3a,
At one end of the fixed shaft 11 protruding toward the pump chamber PR,
An impeller 12 is rotatably supported via a bearing 11a. A plurality of connection holes 12a are formed in the inner diameter side portion of the impeller 12, and these connection holes 12a are
The connection pins 10a of the joint member 10 arranged on the armature shaft 3a are set so as to engage with each other. Thereby, the armature shaft 3a and the impeller 12
Are connected to each other via a connecting member 10, and the impeller 12 is set to rotate integrally with the rotation of the armature shaft 3a.

The impeller 12 has one side surface facing one end or the other end facing the concave portions 8b, 9a of the first and second plates 8, 9 at the inner diameter side portion, and the first side at the outer peripheral side portion. , The outer surface of the second plate 8, 9 is opposed to the inner surface of the second plate 8, between the one end surface of the impeller 12 and the other end surface of the first plate 8, and the other end surface of the impeller 12. A small gap S is formed between the first plate 9 and the one end side surface of the second plate 9 so as to be in a close facing state. Further, on the outer peripheral edge portion of the impeller 12, a blade groove 12b is formed with a predetermined groove width from both side surfaces toward the central portion in the thickness direction of the impeller 12, and is formed so as to be thinner toward the outer diameter side. A plurality is formed in the circumferential direction, whereby
A plurality of closed blade type blades 12 c are formed on the outer periphery of the impeller 12. In the present embodiment, the groove surface shape of the blade groove 12b formed between the adjacent blades 12c is a shape based on a semicycloid curve from the inner diameter side to the outer diameter side. The groove shape of the blade groove 12b is a cycloid curve that is inclined to correspond to the rotation speed and the rotation direction of the impeller 12, and when the impeller 12 rotates, the swirling flow of the fuel approximates to the cycloid curve. It is set to be.

In addition, at the outer diameter portion of the impeller 12 of the second plate 9, that is, at a portion facing the blade groove 12b, an inflow port 9c for allowing fuel to flow into the pump chamber PR is opened. A discharge port 8d for discharging the fuel in the pump chamber PR to the inside of the motor housing 2 is formed in a portion of the one plate 8 opposite to the outer diameter portion of the impeller 12, and an inflow port 9c and a discharge port 8d are formed. Is formed so as to be displaced in the circumferential direction. Further, at the portion of the first and second plates 8, 9 facing the blade groove 12b of the impeller 12, concave grooves 8e, 9d are formed around the circumference except for the discharge port 8d and the inflow port 9c. Thereby, the space between the blade groove 12b and each of the concave grooves 8e and 9d is set as a fuel passage, and the inflow port 9c of the second plate 9 is formed.
The fuel flowing into the pump chamber PR from the outlet is discharged from the discharge port 8d of the first plate 8 via the flow path, and is sent to the inside of the motor housing 2 by pressure. In this case, the shape of the groove surfaces of the concave grooves 8e and 9d is set so as to be a shape based on a cycloid curve when cross-sectioned in a direction perpendicular to the plate thickness of the impeller 12.

Here, the blade groove 12b and the concave groove 8
The shapes of the groove surfaces e and 9d and the fuel swirling state will be described in more detail with reference to FIG. 2 which is a cross section taken along a plane perpendicular to the plate thickness of the impeller 12. By the way, the cycloid curve is a locus of one point on the circumference when the circle rolls on a straight line, and the groove surface of the blade groove 12 of the present embodiment Is set to the locus of a half-rotation while slightly inclining from the inner diameter side to the outer diameter side along the rotation direction. And the semi-cycloid curved blade groove 12b
The groove length defined by the length from the inner-diameter-side groove end A to the outer peripheral edge of the impeller 12 substantially corresponds to pi × radius (πa). Incidentally, the radius a can be calculated from a preset groove depth, and can be set based on pump characteristics such as the plate thickness of the impeller 12 and the amount of discharged fuel.
On the other hand, the concave grooves 8 formed in the first and second plates 8 and 9
The groove surfaces e and 9d correspond to trajectories when the circle having the radius a is rotated once from the inner diameter side on the plate surfaces of the first and second plates 8 and 9, respectively. And the concave groove 8
e, the groove length set by the distance between the inner-diameter groove end B and the outer-diameter groove end C, which are the groove ends in the radial direction of 9d, is pi × diameter (2πa). It is set so as to correspond to twice the groove length of 12b. Further, in the present embodiment, the inner-diameter-side groove ends B of the first and second plates 8 and 9 and the inner-diameter-side groove ends A of the blade grooves 12b are set to be substantially at the same position in the radial direction. It is configured such that there is no step in the flow path.

In the fuel flow path thus formed, the fuel flows as shown by the arrow in FIG.
The outer diameter side, that is, the outer diameter side groove end C of the concave grooves 8e and 9d
It is set so that what is pushed to the side reaches the inner-diameter-side groove end B along the groove surfaces of the concave grooves 8e and 9d. Incidentally, the cycloid curve means that the point M, which is gently released at the initial velocity V1 and reaches the point Y from the point X by gravity drop on the vertical plane shown in FIG. 3, in the shortest time. Therefore, in the pump section P of the present invention in which the fuel flow path is formed by a curved surface based on a cycloid curve, the fuel is set to turn in the fastest state.

In the embodiment of the present invention configured as described above, when the impeller 12 of the pump section P rotates with the rotation of the motor section M, the fuel in the fuel tank is supplied to the second plate inlet. 9c, and is fed into the motor housing 2 from the first plate outlet 8d,
Then, the fuel pumped into the motor housing 2 is discharged from the fuel supply port 7b formed in the cover body 7 to the fuel injection device side.
Blade groove 12b and first and second plate concave grooves 8e, 9d
Are formed on curved surfaces based on cycloid curves, respectively. For this reason, as described above, the fuel that swirls while being guided to the fuel flow path moves in the flow path in the shortest time by swirling in a state approximated to the cycloid curve.
The required flow rate can be secured with a small number of rotations. As a result, the current value of the fuel pump can be reduced to supply the required fuel to the fuel injection device with less power, thereby contributing to improved fuel efficiency.

The present invention is, of course, not limited to the above embodiment, and the blade grooves of the impeller are not necessarily limited to those based on the cycloid curve.
By making the groove surface of the blade based on the cycloid curve as in the above embodiment, it is possible to further increase the pump efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel pump.

FIG. 2 is an enlarged sectional view of a main part.

FIG. 3 is a coordinate diagram illustrating a cycloid curve.

[Explanation of symbols]

 Reference Signs List 1 fuel pump 2 motor housing 3a armature shaft 8 first plate 8c discharge port 8e concave groove 9 second plate 9d concave groove 10 connecting member 12 impeller 12b blade groove M motor part P pump part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F04D 29/44 F04D 29/44 B

Claims (3)

[Claims] A first plate provided on one side of the motor unit and a pump unit provided with an impeller that rotates based on the driving of the motor unit; And a fuel pump comprising a first plate and a second plate, wherein each groove surface of a concave groove provided on an inner surface of the second plate is formed based on a cycloid curve. . 2. The fuel pump according to claim 1, wherein a closed blade is formed on an outer periphery of the impeller, and a blade groove provided to form the closed blade is formed based on a cycloid curve. 3. The fuel pump according to claim 1, wherein a radial groove length of each of the first and second plates is set to substantially half of a radial groove length of the blade groove.